it83xx: lpc: do not clear masks in S0ix -> S0 transition
it83xx: lpc: do not clear masks in S0ix -> S0 transition

Taken from the other LPC drivers. (CL:320191)

Signed-off-by: Dino Li <dino.li@ite.com.tw>

BRANCH=none
BUG=none
TEST=not yet. (Define CONFIG_POWER_S0IX and build EC binary only)

Change-Id: I7438e5ef2a003890b6903a0dd83d0d02161a6b60
Reviewed-on: https://chromium-review.googlesource.com/430477
Commit-Ready: Dino Li <338d523ecf3700bd86eb9c34d220f91911d2a18c@ite.com.tw>
Tested-by: Dino Li <338d523ecf3700bd86eb9c34d220f91911d2a18c@ite.com.tw>
Reviewed-by: Shawn N <5259333ce42e3ace6a73988cec7115ed9d3a661a@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec